kubernetes/kops · error

found VMSS without Linux config

Error message

found VMSS without Linux config

What it means

kOps manages Linux-based nodes, so Find() requires the VMSS osProfile.linuxConfiguration to be set in order to extract SSH settings. If the Azure API returns a scale set without LinuxConfiguration (e.g. it uses Windows, password auth, or an empty osProfile), kOps cannot reconcile it and returns this error.

Source

Thrown at upup/pkg/fi/cloudup/azuretasks/vmscaleset.go:169

		return nil, fmt.Errorf("failed to parse subnet ID %s", *ipConfig.Properties.Subnet.ID)
	}

	var loadBalancerID *azure.LoadBalancerID
	if ipConfig.Properties.LoadBalancerBackendAddressPools != nil {
		for _, i := range ipConfig.Properties.LoadBalancerBackendAddressPools {
			if !strings.Contains(*i.ID, "api") {
				continue
			}
			loadBalancerID, err = azure.ParseLoadBalancerID(*i.ID)
			if err != nil {
				return nil, fmt.Errorf("failed to parse loadbalancer ID %s", *i.ID)
			}
		}
	}

	osProfile := profile.OSProfile
	if osProfile.LinuxConfiguration == nil {
		return nil, fmt.Errorf("found VMSS without Linux config")
	}
	if osProfile.LinuxConfiguration.SSH == nil {
		return nil, fmt.Errorf("found VMSS without SSH config")
	}
	if osProfile.LinuxConfiguration.SSH.PublicKeys == nil {
		return nil, fmt.Errorf("found VMSS without SSH public keys")
	}
	sshKeys := osProfile.LinuxConfiguration.SSH.PublicKeys
	if len(sshKeys) != 1 {
		return nil, fmt.Errorf("expecting exactly 1 SSH key for %q, found %d: %+v", *s.Name, len(sshKeys), sshKeys)
	}

	var userData []byte
	if profile.UserData != nil {
		userData, err = base64.StdEncoding.DecodeString(*profile.UserData)
		if err != nil {
			return nil, fmt.Errorf("failed to decode user data: %w", err)
		}

View on GitHub (pinned to 4c8573c808)

Solutions

1. Verify the VMSS belongs to this kops cluster: `az vmss show -g <rg> -n <vmss>` and check tags/naming; correct the cluster config if kops is looking at the wrong scale set.
2. Recreate the scale set from the kops spec: run `kops update cluster --yes` (or `kops rolling-update cluster`) so it is provisioned with linuxConfiguration and SSH keys.
3. If a custom node image/template dropped linuxConfiguration, fix the template to include linuxConfiguration.disablePasswordAuthentication=true and ssh publicKeys.
4. Never hand-edit VMSS osProfile in kops-managed clusters.

Example fix

// before (ARM/osProfile)
"osProfile": { "adminUsername": "azureuser", "computerNamePrefix": "nodes" }
// after
"osProfile": { "adminUsername": "azureuser", "computerNamePrefix": "nodes", "linuxConfiguration": { "disablePasswordAuthentication": true, "ssh": { "publicKeys": [ { "path": "/home/azureuser/.ssh/authorized_keys", "keyData": "ssh-rsa AAAA..." } ] } } }

func validateLinuxOSProfile(vmss *compute.VirtualMachineScaleSet) error {
  os := vmss.Properties.VirtualMachineProfile.OSProfile
  if os == nil || os.LinuxConfiguration == nil {
    return fmt.Errorf("VMSS %s lacks linuxConfiguration", fi.ValueOf(vmss.Name))
  }
  return nil
}

func hasLinuxConfig(os *compute.VirtualMachineScaleSetOSProfile) bool {
  return os != nil && os.LinuxConfiguration != nil
}

vmss, err := tasks.Find(ctx, cloud, rg, name)
if err != nil {
  if strings.Contains(err.Error(), "without Linux config") {
    // rebuild the scale set via kops update cluster
  }
  return err
}

When it happens

Trigger: Find() on a VMSS whose virtualMachineProfile.osProfile.linuxConfiguration is nil — Windows image scale sets, scale sets configured with password-only auth, or resources created outside kops without linuxConfiguration.

Common situations: A VMSS in the kops-managed resource group was created/modified by hand or by another tool with Windows or password-based osProfile; kops pointing at the wrong resource group/cluster and picking up a foreign VMSS.

Related errors

• found VMSS without SSH config
• found VMSS without SSH public keys
• expecting exactly 1 SSH key for %q, found %d: %+v
• expected exactly one subnet for InstanceGroup %q; subnets wa
• unexpected subnet type: for InstanceGroup %q; type was %s

AI-assisted analysis of kubernetes/kops@4c8573c808 (2026-09-05). Data as JSON: /api/errors/6bb52e1d7b315615. Report an issue: GitHub.